underworld.swarm.layouts module

This module contains classes for populating swarms with particles across the domain.

Module Summary

classes:

underworld.swarm.layouts.PerCellSpaceFillerLayout	This layout fills the domain with particles in a quasi-random pattern.
underworld.swarm.layouts.GlobalSpaceFillerLayout	This layout fills the domain with particles in a quasi-random pattern.
underworld.swarm.layouts.PerCellGaussLayout	This layout populates the domain with particles located at gauss locations within each element of the swarm’s associated finite element mesh.
underworld.swarm.layouts.PerCellRandomLayout	This layout fills the domain with particles in a random (per element) pattern.

Module Details

classes:

class underworld.swarm.layouts.PerCellSpaceFillerLayout(swarm, particlesPerCell, **kwargs)

Bases: underworld.swarm.layouts._PerCellMeshParticleLayout

This layout fills the domain with particles in a quasi-random pattern. It utilises sobol sequences to generate per element particle locations which are more uniform than that achieved by a purely random generator.

Parameters:

• swarm (underworld.swarm.Swarm) – The swarm this layout will act upon
• particlesPerCell (int) – The number of particles per element that this layout will generate.

Example

>>> import underworld as uw
>>> mesh = uw.mesh.FeMesh_Cartesian('Q1/dQ0', (1,1), (0.,0.), (1.,1.))
>>> swarm = uw.swarm.Swarm(mesh)
>>> layout = uw.swarm.layouts.PerCellSpaceFillerLayout(swarm,particlesPerCell=4)
>>> swarm.populate_using_layout(layout)
>>> swarm.particleLocalCount
4
>>> swarm.particleCoordinates.data
array([[ 0.5  ,  0.5  ],
       [ 0.25 ,  0.75 ],
       [ 0.75 ,  0.25 ],
       [ 0.375,  0.625]])

class underworld.swarm.layouts.GlobalSpaceFillerLayout(swarm, particlesPerCell, **kwargs)

Bases: underworld.swarm.layouts._ParticleLayoutAbstract

This layout fills the domain with particles in a quasi-random pattern. It utilises sobol sequences to generate global particle locations which are more uniform than that achieved by a purely random generator. This layout is mostly useful where populating particles across a rectangular domain.

Parameters:

• swarm (underworld.swarm.Swarm) – The swarm this layout will act upon
• particlesPerCell (float) – The average number of particles per element that this layout will generate.

Example

>>> import underworld as uw
>>> mesh = uw.mesh.FeMesh_Cartesian('Q1/dQ0', (1,1), (0.,0.), (1.,1.))
>>> swarm = uw.swarm.Swarm(mesh)
>>> layout = uw.swarm.layouts.GlobalSpaceFillerLayout(swarm,particlesPerCell=4)
>>> swarm.populate_using_layout(layout)
>>> swarm.particleLocalCount
4
>>> swarm.particleCoordinates.data
array([[ 0.5  ,  0.5  ],
       [ 0.25 ,  0.75 ],
       [ 0.75 ,  0.25 ],
       [ 0.375,  0.625]])

class underworld.swarm.layouts.PerCellGaussLayout(swarm, gaussPointCount, **kwargs)

Bases: underworld.swarm.layouts._ParticleLayoutAbstract

This layout populates the domain with particles located at gauss locations within each element of the swarm’s associated finite element mesh.

Parameters:

• swarm (underworld.swarm.Swarm) – The swarm this layout will act upon
• gaussPointCount (int) – Per cell, the number of gauss points in each dimensional direction. Must take an int value between 1 and 5 inclusive.

Example

>>> import underworld as uw
>>> # choose mesh to coincide with global element
>>> mesh = uw.mesh.FeMesh_Cartesian('Q1/dQ0', (1,1), (-1.,-1.), (1.,1.))
>>> swarm = uw.swarm.Swarm(mesh)
>>> layout = uw.swarm.layouts.PerCellGaussLayout(swarm,gaussPointCount=2)
>>> swarm.populate_using_layout(layout)
>>> swarm.particleLocalCount
4
>>> swarm.particleCoordinates.data
array([[-0.57735027, -0.57735027],
       [ 0.57735027, -0.57735027],
       [-0.57735027,  0.57735027],
       [ 0.57735027,  0.57735027]])
>>> import math
>>> # lets check one of these gauss points
>>> ( swarm.particleCoordinates.data[3][0] - math.sqrt(1./3.) ) < 1.e-10
True

class underworld.swarm.layouts.PerCellRandomLayout(swarm, particlesPerCell, seed=13, **kwargs)

Bases: underworld.swarm.layouts._PerCellMeshParticleLayout

This layout fills the domain with particles in a random (per element) pattern.

Parameters:

• swarm (underworld.swarm.Swarm) – The swarm this layout will act upon
• particlesPerCell (int) – The number of particles per element that this layout will generate.
• seed (int) – Seed for random generator. Default is 13.

Example

>>> import underworld as uw
>>> mesh = uw.mesh.FeMesh_Cartesian('Q1/dQ0', (1,1), (0.,0.), (1.,1.))
>>> swarm = uw.swarm.Swarm(mesh)
>>> layout = uw.swarm.layouts.PerCellRandomLayout(swarm,particlesPerCell=4)
>>> swarm.populate_using_layout(layout)
>>> swarm.particleLocalCount
4
>>> swarm.particleCoordinates.data
array([[ 0.24261743,  0.67115852],
       [ 0.16116546,  0.70790335],
       [ 0.73160516,  0.08792286],
       [ 0.71953113,  0.15966135]])